1. Field of the Invention
The present invention relates to an electric-current biosensor, and particularly to an electric-current biosensor that can increase electric-current on a conductive film for testing blood glucose concentration more accurately.
2. Description of the Prior Art
The present simple way of blood glucose determination usually uses an electric-current biosensor and applies a blood sample on the biosensor. The biosensor will accrue oxidation-reduction reaction with the sample and produce electric ions. The ions accrue an electric current on the electric-current biosensor. Then, the electric-current biosensor is inserted into a meter for comparing and analyzing the current, thereby determining the blood glucose concentration.
The applicant has received R.O.C. Patent No. 541942 for an electric-current biosensor. It improved the disadvantage of small reaction area and provided a larger electrode contacting area for lifting the determination accuracy. Referring to the FIGS. 1 and 2, unfolded top and folded top views of biosensors according to the prior art are shown. The biosensor has a support 10, electrode film 20, conductive film 30, bioactivity layer 40, and an adhesive layer 50. The biosensor 10 has a first support 11′ a second support 12, and a folding line 13′ is formed between the first support 11′ and the second support 12 for covering the second support 12 on the first support 11′. The second support 12 is shorter than the first support 11′ and is formed with a testing opening 121. The electrode film 20 has a first electrode film 21 and a second electrode film 22. The first electrode film 21 is disposed on the first support 11′ and has a positive electrode film 23 and a negative electrode film 24. The second electrode film 22 is disposed on the second support 12 and around the testing opening 121. The conductive film 30 is disposed on the first support 11′, and has a positive conductive film 31 and a negative conductive film 32 separate from the positive conductive film 31. The positive and negative conductive films are electrically connected to the positive electrode film 23 and the negative electrode film 24, respectively. The bioactivity layer 40 is disposed on the first electrode film 21, and formed with an activity area 41. The activity area 41 covers at least some portions of the first positive electrode film 23 and the negative electrode film 24. The second support 12 is formed with a mating activity area 16 corresponding to the activity area 41, and the mating activity area 16 is against and close to the activity area 41 when the second support 12 covers the first support 11′. The adhesive layer 50 is disposed on the second support 12 and does not cover the mating activity area 16 and an operating area 51 formed on an end of the second support 12.
When applying the blood sample into the testing opening 121, the sample and the activity area 41 of the bioactivity layer 40 will causes a reaction and release electric ions. The ions will act between the electrode film 20 and the conductive film 30, then the biosensor further cooperates with a meter for comparing the current and analyzing the glucose concentration to get the blood glucose concentration.
Although the prior art raises the accuracy of blood glucose determination, it still has areas, which could be improved. For example, it is not so easy to apply the blood sample into the testing opening 121. Application of the blood sample to the biosensor rather than into the testing opening 121 is a source of inconvenience to the user. Moreover, after the blood sample is applied into the testing opening 121, it mainly spreads vertically toward the positive electrode film 23 and the negative electrode film 24. The ions spread less in the horizontal direction. However, the positive electrode film 23 and the negative electrode film 24 are arranged parallel along a horizontal direction, and the spreading direction of the ions results in a weak current in the horizontal direction.
Therefore, the electric-current biosensor of the prior art still has some inconveniences and disadvantages to be improved. The inventor, after investigation and research, thus provides the present invention of logical design for improving the above-mentioned imperfections.